Wireless telecommunications systems have enjoyed great acceptance by telecommunications system providers and by telecommunications service customers. A significant number of customers of wireless services use their wireless telephones for multiple functional roles. For example, many wireless customers use a wireless telephone for both business and personal calls. Many customers do not desire to carry two or more wireless telephones, and therefore they use a single telephone for work-related calls, personal calls, and calls associated with any other functional roles they may have.
A problem with using a single telephone for multiple roles is that it is often desirable to separately account for expenses associated with calls for each of these roles. For example, although a customer may use a single telephone for personal and business calls, the customer often desires that business calls be separately accounted for, so that the customer may seek reimbursement from an employer or obtain favorable tax treatment of the expenses. Also, some wireless telephones may be shared by two people, who may wish separate accounting of their calls.
In addition, it is often desirable that calls be handled differently depending on the different roles with which a call may be associated. For example, the customer may desire that business calls be forwarded to a voice messaging system, but personal calls be delivered, during non-working periods. For another example, the customer may desire that personal calls be forwarded or blocked during an important business meeting, but may be willing to accept business calls during the meeting.
Some wireless telecommunications systems, such as the GSM wireless system, allow multiple directory numbers to be assigned to a single wireless telephone or wireless service subscription. However, as these systems historically have been implemented, for outgoing calls, there have been provided no facilities to permit the wireless customer to conveniently direct, on a per-call basis, the particular one of two or more “lines”, subscriptions, or billing numbers to which charges for the call should be billed. Similarly, for incoming calls in systems having separate Gateway Mobile Switching Center (GMSC) and Visitor Mobile Switching Center (VMSC) elements (the desirable case in large networks), there have been provided no facilities to separately account for calls destined for various directory or billing numbers assigned to a single wireless telephone. Further, for incoming calls, there have been provided no facilities to separately control the handling (e.g., forwarding, blocking, etc.) of calls destined for various directory or billing numbers.
In addition, there have been provided no means to indicate to a user when an incoming call arrives at a wireless telephone having multiple assigned numbers the particular one of several assigned numbers to which the call was originally directed. This makes it difficult for the subscriber to know, for example, whether an incoming call is a business or personal call. Where a telephone is shared, it is difficult to determine to which user an incoming call is directed.
It is believed that at least one standards body is considering a revision to the GSM standards, under which additional features would be added to wireless telephones, and certain aspects of the standardized signaling protocol between the wireless telephone and the wireless network infrastructure would be changed, to accommodate the assignment and use of two billing numbers with a single wireless phone. It should be noted that there are many tens of millions of customers of wireless telecommunications systems, and each of these already have one or more wireless telephones complying with the existing or prior versions of the standards. Thus, one complication of addressing the disadvantages of existing wireless telecommunications systems by adding features to the telephone and changing the signaling protocol between the telephone and the network infrastructure is that it would be extremely costly to replace or upgrade the installed base of wireless telephones to provide new facilities supporting multiple directory or billing numbers. Even if the wireless customer were not required to directly pay for the replacement or upgrade, significant customer resentment could be expected.